1/* Verify that DSO is unloaded only if its TLS objects are destroyed.
2 Copyright (C) 2013-2024 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19/* For the default case, i.e. NO_DELETE not defined, the test dynamically loads
20 a DSO and spawns a thread that subsequently calls into the DSO to register a
21 destructor for an object in the DSO and then calls dlclose on the handle for
22 the DSO. When the thread exits, the DSO should not be unloaded or else the
23 destructor called during thread exit will crash. Further in the main
24 thread, the DSO is opened and closed again, at which point the DSO should be
25 unloaded.
26
27 When NO_DELETE is defined, the DSO is loaded twice, once with just RTLD_LAZY
28 flag and the second time with the RTLD_NODELETE flag set. The thread is
29 spawned, destructor registered and then thread exits without closing the
30 DSO. In the main thread, the first handle is then closed, followed by the
31 second handle. In the end, the DSO should remain loaded due to the
32 RTLD_NODELETE flag being set in the second dlopen call. */
33
34#include <pthread.h>
35#include <stdio.h>
36#include <unistd.h>
37#include <string.h>
38#include <errno.h>
39#include <link.h>
40#include <stdbool.h>
41#include <support/xdlfcn.h>
42
43#ifndef NO_DELETE
44# define LOADED_IS_GOOD false
45#endif
46
47#ifndef H2_RTLD_FLAGS
48# define H2_RTLD_FLAGS (RTLD_LAZY)
49#endif
50
51#define DSO_NAME "$ORIGIN/tst-tls-atexit-lib.so"
52
53/* Walk through the map in the _r_debug structure to see if our lib is still
54 loaded. */
55static bool
56is_loaded (void)
57{
58 struct link_map *lm = (struct link_map *) _r_debug.r_map;
59
60 for (; lm; lm = lm->l_next)
61 if (lm->l_type == lt_loaded && lm->l_name
62 && strcmp (basename (DSO_NAME), basename (lm->l_name)) == 0)
63 {
64 printf (format: "%s is still loaded\n", lm->l_name);
65 return true;
66 }
67 return false;
68}
69
70/* Accept a valid handle returned by DLOPEN, load the reg_dtor symbol to
71 register a destructor and then call dlclose on the handle. The dlclose
72 should not unload the DSO since the destructor has not been called yet. */
73static void *
74reg_dtor_and_close (void *h)
75{
76 void (*reg_dtor) (void) = (void (*) (void)) xdlsym (handle: h, symbol: "reg_dtor");
77
78 reg_dtor ();
79
80#ifndef NO_DELETE
81 xdlclose (h);
82#endif
83
84 return NULL;
85}
86
87static int
88spawn_thread (void *h)
89{
90 pthread_t t;
91 int ret;
92 void *thr_ret;
93
94 if ((ret = pthread_create (newthread: &t, NULL, start_routine: reg_dtor_and_close, arg: h)) != 0)
95 {
96 printf (format: "pthread_create failed: %s\n", strerror (errnum: ret));
97 return 1;
98 }
99
100 if ((ret = pthread_join (th: t, thread_return: &thr_ret)) != 0)
101 {
102 printf (format: "pthread_join failed: %s\n", strerror (errnum: ret));
103 return 1;
104 }
105
106 if (thr_ret != NULL)
107 return 1;
108
109 return 0;
110}
111
112static int
113do_test (void)
114{
115 /* Load the DSO. */
116 void *h1 = xdlopen (DSO_NAME, RTLD_LAZY);
117
118#ifndef NO_DELETE
119 if (spawn_thread (h1) != 0)
120 return 1;
121#endif
122
123 void *h2 = xdlopen (DSO_NAME, H2_RTLD_FLAGS);
124
125#ifdef NO_DELETE
126 if (spawn_thread (h: h1) != 0)
127 return 1;
128
129 xdlclose (handle: h1);
130#endif
131 xdlclose (handle: h2);
132
133 /* Check link maps to ensure that the DSO has unloaded. In the normal case,
134 the DSO should be unloaded if there are no uses. However, if one of the
135 dlopen calls were with RTLD_NODELETE, the DSO should remain loaded. */
136 return is_loaded () == LOADED_IS_GOOD ? 0 : 1;
137}
138
139#define TEST_FUNCTION do_test ()
140#include "../test-skeleton.c"
141

source code of glibc/stdlib/tst-tls-atexit.c